Dissertation > Excellent graduate degree dissertation topics show

Study on the Lead-free High Curie Temperature BaTiO3 Based Materials

Author: KangJianNing
Tutor: QuYuanFang
School: Tianjin University
Course: Materials Science
Keywords: BNT lead-free high Curie temperature BaCO3 air sintering
CLC: TB302
Type: Master's thesis
Year: 2010
Downloads: 88
Quote: 0
Read: Download Dissertation

Abstract


In order to prepare the lead-free PTC ceramics with high Curie temperature (Tc), the BaTiO3-based PTC materials were studied in this paper. The BT/BNT PTC materials were prepared by compounding BNT with high Tc, and the property and influence factor of the composites were investigated through some test methods, such asρ-T curve measuring,ε-T curve measuring, XRD and so on.The Curie temperature of BNT is 320℃, and it could be solid solutions with BT. It was better for semiconducting by adding the pre-synthesized BNT into the second materials than any other methods and the Tc of the composites could also be improved by this way. However, the addition of BNT had side effects too. The free state Na created by the decomposition of BNT during high temperature sintering had some bad effects on semiconducting. Moreover, the more addition of BNT was, the more serious the effects were. When the addition of BNT was over 1mol%, the original samples could not be semiconducting by air sintering. It was found that the incorporation of A-site substitutes BaCO3 could efficiently inhibit the decomposition of BNT, which made the air sintering samples semiconducting. The optimum adding quantity of BaCO3 was 3%. By comparing with some other donor dopants, Y2O3 was found better for the samples’semiconducting. By investigating the addition of acceptor dopant MnO2, it was also found that the right donor-acceptor ratio was helpful to the improvement of the properties of the PTC composites. When the addition of Y2O3 was 0.2mol% and the addition of MnO2 was 0.1mol%, the samples’room temperature resistivity is 1142Ω·cm and the resistance jump is 665. The incorporation of BNT could outstandingly improve the samples’Curie temperature. That was because the addition of BNT could strengthen Ti-O bond and enhance the tetragonality of the ceramic crystal lattice. When the addition of BNT is 2mol%, the Curie temperature increased from 120℃to 148℃, which made it possible to prepare the lead-free BaTiO3-based PTC ceramics with high Tc by BNT instead of PbTiO3.

Related Dissertations

  1. Preparation and Properties of lead-free glass powder,TQ171.6
  2. Fabrication and Ferroelectric Properties of BNT and BFO and BNT/BNT Composite Thin Films,TP333;O484.1
  3. Study on LTCC of BNT System Ceramic Materials,TQ174.1
  4. Study on (Bi0.5Na0.5TiO3-based and High Temperature Aurivillius Phase Lead-free Piezoceramics,TM282
  5. Research of the Lead-free High-curie Temperature PTC Materials,TN304
  6. The Application of Surface Nanocone Array Technology in Lead-free Pd PPF Lead Frame,TB383.1
  7. Influence of Cooling Rates on Microstructure and Properties of Zn-4Al-3Mg Alloy,TG146.13
  8. Effect of Trace Phosphorus on the Oxidation Resistance of Lead-Free Solder Used in Wave Soldering,TG425
  9. Research on the New Lead-Free Solder Processing Properties of Brazing and Mechanical Properties,TG454
  10. Residual Stress in BNT and PZT Ferroelectric Thin Films,TB383.2
  11. Bi_ (0.5 ) of Na_ ( 0.5 ) TiO_3 base electrical properties of lead-free piezoelectric ceramics,TM282
  12. Research on Bending Performance and Brazing Perform Ance of Copper Alloy Material Used for Lead Frame,TG146.11
  13. The Improvement of the Solder Paste Performance and the Effect of Composition on It,TG42
  14. Effect of Cerium on Property and Microstructure for SnAgCu Lead Free Solder,TG425
  15. Corrosion Research of Different Lead Free Wave Solder Pot Materials,TG425
  16. Finite Element Simulation of Reliability and Life Prediction on Solder Joint of MCM,TG453.9
  17. Study on Properties of Alkali Metals Niobate Lead Free Piezoelectric Ceramics,TQ174.7
  18. Study on Compressive Creep Properties of the Sn-Zn Lead-free Solder,TG425
  19. Research on SnAgCu Solder Alloys,TG42
  20. A Study of the Creep Property of Sn-9Zn Solder and Its Strengthen,TG425

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > General issues of engineering materials > Engineering and materials testing
© 2012 www.DissertationTopic.Net  Mobile